Spontaneous activity competes externally evoked responses in sensory cortex

SummaryThe functional role of spontaneous brain activity, especially in relation to external events, is a longstanding key question in neuroscience. Intrinsic and externally-evoked activities were suggested to be anticorrelated, yet inferring an antagonistic mechanism between them remains a challenge. Here, we used beta-band (15-30 Hz) power as a proxy of spontaneous activity in the rat somatosensory cortex during a detection task. Beta-power anticorrelated with sensory-evoked-responses, and high rates of spontaneously occurring beta-bursts predicted reduced detection. By applying a burst-rate detection algorithm in real-time and trial-by-trial stimulus-intensity adjustment, this influence could be counterbalanced. Mechanistically, bursts in all bands indicated transient synchronization of cell assemblies, but only beta-bursts were followed by a reduction in firing-rate. Our findings reveal that spontaneous beta-bursts reflect a dynamic state that competes with external stimuli.

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Spontaneous activity competes with externally evoked responses in sensory cortex

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2023286118 ◽

2021 ◽

Vol 118 (25) ◽

pp. e2023286118

Author(s):

Golan Karvat ◽

Mansour Alyahyay ◽

Ilka Diester

Keyword(s):

Real Time ◽

Closed Loop ◽

Underlying Mechanism ◽

Dynamic State ◽

Evoked Responses ◽

Beta Band ◽

Beta Power ◽

Adjustment System ◽

Sensory Evoked ◽

External Stimuli

The interaction between spontaneous and externally evoked neuronal activity is fundamental for a functional brain. Increasing evidence suggests that bursts of high-power oscillations in the 15- to 30-Hz beta-band represent activation of internally generated events and mask perception of external cues. Yet demonstration of the effect of beta-power modulation on perception in real time is missing, and little is known about the underlying mechanism. Here, we used a closed-loop stimulus-intensity adjustment system based on online burst-occupancy analyses in rats involved in a forepaw vibrotactile detection task. We found that the masking influence of burst occupancy on perception can be counterbalanced in real time by adjusting the vibration amplitude. Offline analysis of firing rates (FRs) and local field potentials across cortical layers and frequency bands confirmed that beta-power in the somatosensory cortex anticorrelated with sensory evoked responses. Mechanistically, bursts in all bands were accompanied by transient synchronization of cell assemblies, but only beta-bursts were followed by a reduction of FR. Our closed loop approach reveals that spontaneous beta-bursts reflect a dynamic state that competes with external stimuli.

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Spatiotemporal structure of sensory-evoked and spontaneous activity revealed by mesoscale imaging in anesthetized and awake mice

10.1101/2020.05.22.111021 ◽

2020 ◽

Cited By ~ 1

Author(s):

Navvab Afrashteh ◽

Samsoon Inayat ◽

Edgar Bermudez Contreras ◽

Artur Luczak ◽

Bruce L. McNaughton ◽

...

Keyword(s):

Spontaneous Activity ◽

Brain Activity ◽

Activity Patterns ◽

Sensory Stimulation ◽

Wide Field ◽

Evoked Responses ◽

Evoked Activity ◽

Cortical Regions ◽

The One ◽

Sensory Evoked

AbstractBrain activity propagates across the cortex in diverse spatiotemporal patterns, both as a response to sensory stimulation and during spontaneous activity. Despite been extensively studied, the relationship between the characteristics of such patterns during spontaneous and evoked activity is not completely understood. To investigate this relationship, we compared visual, auditory, and tactile evoked activity patterns elicited with different stimulus strengths and spontaneous activity motifs in lightly anesthetized and awake mice using mesoscale wide-field voltage-sensitive dye and glutamate imaging respectively. The characteristics of cortical activity that we compared include amplitude, speed, direction, and complexity of propagation trajectories in spontaneous and evoked activity patterns. We found that the complexity of the propagation trajectories of spontaneous activity, quantified as their fractal dimension, is higher than the one from sensory evoked responses. Moreover, the speed and direction of propagation, are modulated by the amplitude during both, spontaneous and evoked activity. Finally, we found that spontaneous activity had similar amplitude and speed when compared to evoked activity elicited with low stimulus strengths. However, this similarity gradually decreased when the strength of stimuli eliciting evoked responses increased. Altogether, these findings are consistent with the fact that even primary sensory areas receive widespread inputs from other cortical regions, and that, during rest, the cortex tends to reactivate traces of complex, multi-sensory experiences that may have occurred in a range of different behavioural contexts.

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Neural responses to heartbeats as a mechanism for distinguishing self from other during imagination

10.1101/414573 ◽

2018 ◽

Author(s):

Mariana Babo-Rebelo ◽

Anne Buot ◽

Catherine Tallon-Baudry

Keyword(s):

Brain Activity ◽

Cardiac Activity ◽

The Body ◽

Evoked Responses ◽

Posterior Cingulate ◽

Person Perspective ◽

Third Person ◽

Third Person Perspective ◽

Neural Monitoring ◽

External Stimuli

AbstractImagination is an internally-generated process, where one can make oneself or other people appear as protagonists of a scene. How does the brain tag the protagonist of an imagined scene, as being oneself or someone else? Crucially, neither external stimuli nor motor feedback are available during imagination to disentangle imagining oneself from imagining someone else. Here, we test the hypothesis that an internal mechanism based on the neural monitoring of heartbeats could distinguish between self and other. 23 participants imagined themselves (from a first-person perspective) or a friend (from a third-person perspective) in various scenarios, while their brain activity was recorded with magnetoencephalography and their cardiac activity was simultaneously monitored. We measured heartbeat-evoked responses, i.e. transients of neural activity occurring in response to each heartbeat, during imagination. The amplitude of heartbeat-evoked responses differed between imagining oneself and imagining a friend, in the precuneus, mid and posterior cingulate regions bilaterally. Effect size was modulated by the general daydreaming frequency of participants but not by their interoceptive abilities. These results could not be accounted for by other characteristics of imagination (e.g., the ability to adopt the perspective, valence or arousal), nor by cardiac parameters (e.g., heart rate) or arousal levels. Heartbeat-evoked responses thus appear as a neural marker distinguishing self from other during imagination.Highlights- Heartbeat-evoked responses differentiate self from other during imagination.- These effects were located in the precuneus and mid- to posterior cingulate.- The neural monitoring of the body could be a mechanism for self/other distinction.

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Beyond the Passive/Active Dichotomy: A Spectrum Model of the Brain’s Neural Activities

The Spontaneous Brain ◽

10.7551/mitpress/9780262038072.003.0001 ◽

2018 ◽

pp. 3-26

Author(s):

Georg Northoff

Keyword(s):

Spontaneous Activity ◽

Empirical Data ◽

Resting State ◽

Brain Activity ◽

Empirical Support ◽

Theoretical Issue ◽

Active Model ◽

External Stimuli ◽

The Brain ◽

Spectrum Model

Neuroscience has made considerable progress over the last decades in revealing neuronal mechanisms on different levels of brain activity including genetic, molecular, cellular, regional and network levels. However, despite all this progress, no particular model of the brain has commanded consensus. A model of the brain should attribute clear features to the brain, such as its degree of participation in its own processing of stimuli. While primarily a theoretical issue, models of the brain may create major reverberations within neuroscientific investigation and philosophical work on the mind-brain problem. Both philosophers and neuroscientists often presuppose a passive model of the brain wherein the brain passively receives and processes external stimuli. However, recent empirical data do not support a passive view of the brain. Accordingly, I will advocate for an active model of the brain. The empirical support for an active model of brain comes from findings concerning its resting state or spontaneous activity. Empirical data shows that the brain’s stimulus-induced activity results from the integration of spontaneous activity and external stimuli. However, the brain’s activity can vary with respect to the extent of integration of resting state activity and external stimuli. This leads me to suggest what I describe as a spectrum model of the brain. The spectrum model claims that stimulus-induced activity is based on a spectrum or continuum of different possible relationships or balances between spontaneous activity and external stimuli.

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Brain rhythms shift and deploy attention

10.1101/795567 ◽

2019 ◽

Author(s):

Craig G. Richter ◽

Conrado A. Bosman ◽

Julien Vezoli ◽

Jan-Mathijs Schoffelen ◽

Pascal Fries

Keyword(s):

Left Hemisphere ◽

Striate Cortex ◽

Brain Activity ◽

Premotor Cortex ◽

High Specificity ◽

Beta Band ◽

Brain Rhythms ◽

Macaque Monkeys ◽

Beta Power ◽

High Beta

AbstractOne of the most central cognitive functions is attention. Its neuronal underpinnings have primarily been studied during conditions of sustained attention. Much less is known about the neuronal dynamics underlying the processes of shifting attention in space, as compared to maintaining it on one stimulus, and of deploying it to a particular stimulus. Here, we use ECoG to investigate four rhythms across large parts of the left hemisphere of two macaque monkeys during a task that allows investigation of deployment and shifting. Shifting involved a strong transient enhancement of power in a 2-7 Hz theta band in frontal, pre-motor and visual areas, and reductions of power in an 11-20 Hz beta band in a fronto-centro-parietal network and in a 29-36 Hz high-beta band in premotor cortex. Deployment of attention to the contralateral hemifield involved an enhancement of beta power in parietal areas, a concomitant reduction of high-beta power in pre-motor areas and an enhancement of power in a 60-76 Hz gamma band in extra-striate cortex. Effects due to shifting occurred earlier than effects due to deployment. These results demonstrate that the four investigated rhythms are involved in attentional allocation, with striking differences between shifting and deployment between different brain areas.SignificanceWe are often confronted by many visual stimuli, and attentional mechanisms select one stimulus for in-depth processing. This involves that attention is shifted between stimuli and deployed to one stimulus at a time. Prior studies have revealed that these processes are subserved by several brain rhythms. Therefore, we recorded brain activity in macaque monkeys with many electrodes distributed over large parts of their left hemisphere, while they performed a task that involved shifting and deploying attention. We found four dominant rhythms: theta (2-7 Hz), beta (11-20 Hz), high-beta (29-36 Hz) and gamma (60-76 Hz). Attentional shifting and deployment involved dynamic modulations in the strength of those rhythms with high specificity in space and time.

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Faculty Opinions recommendation of The effects of tonic locus ceruleus output on sensory-evoked responses of ventral posterior medial thalamic and barrel field cortical neurons in the awake rat.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1022940.264694 ◽

2004 ◽

Author(s):

Gary Aston-Jones

Keyword(s):

Cortical Neurons ◽

Locus Ceruleus ◽

Evoked Responses ◽

Barrel Field ◽

Awake Rat ◽

Sensory Evoked

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Clinical Validation of the Champagne Algorithm for Evoked Response Source Localization in Magnetoencephalography

Brain Topography ◽

10.1007/s10548-021-00850-4 ◽

2021 ◽

Author(s):

Abhishek S. Bhutada ◽

Chang Cai ◽

Danielle Mizuiri ◽

Anne Findlay ◽

Jessie Chen ◽

...

Keyword(s):

Evoked Potentials ◽

Source Localization ◽

Clinical Population ◽

Evoked Responses ◽

Localization Algorithm ◽

Equivalent Current Dipole ◽

Current Dipole ◽

Tumor Patients ◽

Equivalent Current ◽

Sensory Evoked

AbstractMagnetoencephalography (MEG) is a robust method for non-invasive functional brain mapping of sensory cortices due to its exceptional spatial and temporal resolution. The clinical standard for MEG source localization of functional landmarks from sensory evoked responses is the equivalent current dipole (ECD) localization algorithm, known to be sensitive to initialization, noise, and manual choice of the number of dipoles. Recently many automated and robust algorithms have been developed, including the Champagne algorithm, an empirical Bayesian algorithm, with powerful abilities for MEG source reconstruction and time course estimation (Wipf et al. 2010; Owen et al. 2012). Here, we evaluate automated Champagne performance in a clinical population of tumor patients where there was minimal failure in localizing sensory evoked responses using the clinical standard, ECD localization algorithm. MEG data of auditory evoked potentials and somatosensory evoked potentials from 21 brain tumor patients were analyzed using Champagne, and these results were compared with equivalent current dipole (ECD) fit. Across both somatosensory and auditory evoked field localization, we found there was a strong agreement between Champagne and ECD localizations in all cases. Given resolution of 8mm voxel size, peak source localizations from Champagne were below 10mm of ECD peak source localization. The Champagne algorithm provides a robust and automated alternative to manual ECD fits for clinical localization of sensory evoked potentials and can contribute to improved clinical MEG data processing workflows.

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Mind-wandering Is Accompanied by Both Local Sleep and Enhanced Processes of Spatial Attention Allocation

Cerebral Cortex Communications ◽

10.1093/texcom/tgab001 ◽

2021 ◽

Vol 2 (1) ◽

Author(s):

Christian Wienke ◽

Mandy V Bartsch ◽

Lena Vogelgesang ◽

Christoph Reichert ◽

Hermann Hinrichs ◽

...

Keyword(s):

Search Task ◽

Brain Activity ◽

Target Selection ◽

Mind Wandering ◽

Attentional Selection ◽

Self Report ◽

Cortical Processing ◽

High Frequency Activity ◽

External Stimuli ◽

Local Sleep

Abstract Mind-wandering (MW) is a subjective, cognitive phenomenon, in which thoughts move away from the task toward an internal train of thoughts, possibly during phases of neuronal sleep-like activity (local sleep, LS). MW decreases cortical processing of external stimuli and is assumed to decouple attention from the external world. Here, we directly tested how indicators of LS, cortical processing, and attentional selection change in a pop-out visual search task during phases of MW. Participants’ brain activity was recorded using magnetoencephalography, MW was assessed via self-report using randomly interspersed probes. As expected, the performance decreased under MW. Consistent with the occurrence of LS, MW was accompanied by a decrease in high-frequency activity (HFA, 80–150 Hz) and an increase in slow wave activity (SWA, 1–6 Hz). In contrast, visual attentional selection as indexed by the N2pc component was enhanced during MW with the N2pc amplitude being directly linked to participants’ performance. This observation clearly contradicts accounts of attentional decoupling that would predict a decrease in attention-related responses to external stimuli during MW. Together, our results suggest that MW occurs during phases of LS with processes of attentional target selection being upregulated, potentially to compensate for the mental distraction during MW.

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An Analysis of the External Validity of EEG Spectral Power in an Uncontrolled Outdoor Environment during Default and Complex Neurocognitive States

Brain Sciences ◽

10.3390/brainsci11030330 ◽

2021 ◽

Vol 11 (3) ◽

pp. 330

Author(s):

Dalton J. Edwards ◽

Logan T. Trujillo

Keyword(s):

External Validity ◽

Spectral Power ◽

Brain Activity ◽

Outdoor Environment ◽

Oscillatory Activity ◽

Brain State ◽

Beta Band ◽

Eeg Spectral Power ◽

Eeg Power ◽

Human Participants

Traditionally, quantitative electroencephalography (QEEG) studies collect data within controlled laboratory environments that limit the external validity of scientific conclusions. To probe these validity limits, we used a mobile EEG system to record electrophysiological signals from human participants while they were located within a controlled laboratory environment and an uncontrolled outdoor environment exhibiting several moderate background influences. Participants performed two tasks during these recordings, one engaging brain activity related to several complex cognitive functions (number sense, attention, memory, executive function) and the other engaging two default brain states. We computed EEG spectral power over three frequency bands (theta: 4–7 Hz, alpha: 8–13 Hz, low beta: 14–20 Hz) where EEG oscillatory activity is known to correlate with the neurocognitive states engaged by these tasks. Null hypothesis significance testing yielded significant EEG power effects typical of the neurocognitive states engaged by each task, but only a beta-band power difference between the two background recording environments during the default brain state. Bayesian analysis showed that the remaining environment null effects were unlikely to reflect measurement insensitivities. This overall pattern of results supports the external validity of laboratory EEG power findings for complex and default neurocognitive states engaged within moderately uncontrolled environments.

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